<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8"/>
    <title>单个爱心跳动</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        html, body {
            width: 100%;
            height: 100%;
        }

        body {
            background: pink;
            display: flex;
            flex-direction: row;
            justify-content: center;
            align-items: center;
        }

        .heart {
            width: 200px;
            height: 200px;
            background-color: red;
            position: relative;
            transform: rotate(45deg);
            animation: heartbeat 0.8s alternate infinite;
            box-shadow: 0 0 30px red;
        }

        .heart::before {
            content: "";
            width: 200px;
            height: 100px;
            background-color: red;
            position: absolute;
            left: 0;
            top: -99px;
            border-radius: 100px 100px 0 0;
            box-shadow: 0 0 30px red;
        }

        .heart::after {
            content: "";
            width: 100px;
            height: 200px;
            background-color: red;
            position: absolute;
            left: -99px;
            top: 0;
            border-radius: 100px 0 0 100px;
            box-shadow: 0 0 30px red;
        }

        @keyframes heartbeat {
            0% {
                transform: rotate(45deg) scale(0.6);
            }
            100% {
                transform: rotate(45deg) scale(1.4);
            }
        }
    </style>
</head>
<body>

<div class="heart"></div>

</body>
</html>